Adjustable concrete column form and panel therefor



Jan. 9, 1968 J. R. GILBERT 3,362,674

I ADJUSTABLE CONCRETE COLUMN FORM AND PANEL THEREFOR Filed April 14, 1965 3 Sheets-Sheet 1 flVVE/VTOR dQ /N R. G/LBERT ATTORNEY Jan. 9, 1968 J. R. GILBERT 3,362,674

ADJUSTABLHCONCRETE COLUMN FORM AND PANEL THEREFOR Filed April 14, 1965 3 Sheets-Sheet 5 United States Patent 3,362,674 ADJUSTABLE CONCRETE COLUMN FORM AND PANEL THEREFOR John R. Gilbert, (Ihicago, Ill., assignor to Symons Mfg. Company, Des Plaines, 111., a corporation of Delaware Filed Apr. 14, 1965, Ser. No. 448,083 2 illaims. (Cl. 249-49) The present invention relates generally to concrete column forms and has particular reference to a novel adjustable concrete column form comprising specially constructed rectangular panels which are capable, by the use of conventional or standard concrete form hardware, of being assembled in various ways upon one another in order to accommodate or provide for the erection of concrete columns in varying sizes, that is, horizontal dimensions. The invention is particularly concerned with a concrete column forrn which is designed for use in connection with the erection of concrete columns of rectangular cross section.

In the erection of a tall multi-story building, such, for example, as a large office or high rise building, the employed rectangular concrete columns diminish in size progressively and vertically upwardly as the building, during the course of construction, progresses. Thus, the forms which are employed in the lower levels of the building are not ordinarily suitable for use in the intermediate and upper levels thereof and the contractor is obliged to have on hand a large inventory of concrete column form panels of different sizes and to transport such panels to and from the construction site.

The present invention contemplates a novel concrete column erection system comprising a series of concrete column form panels which, although of a predetermined uniform size, are capable in any given building installation of accommodating or forming large and small concrete columns, as well as concrete columns of a wide variety of intermediate sizes. Moreover, in connection with the system, the panels are reuseable in the same building installation, substantially without modification, so that after a given number of panels have served in the creation or formation of a large column at one level of the building, the panels may, as soon as the concrete has hardened sufficiently to warrant their removal, be stripped from the column and used again in the creation of a smaller column at a higher building level.

The concrete column form panels of the present invention are known in the concrete construction field as Steel- Ply panels and are manufactured and sold by Symons Mfg. Company of Des Plaines, Ill. Steel-Ply panels, in various forms, are widely used in the building industry. They are assembled at the factory rather than in the field, and when shipped to a given scene of concrete construction, they are designed to be used with various articles of concrete hardware, which are of special construction and permit the panels to be quickly and easily erected in a wall form or column form installation and subsequently removed from the installation for reuse after they have served their purpose. Heretofore, when such Steel-Ply panels have been employed for rectangular building column work, it has been necessary either to manufacture them in special dimensions which depart from standard dimensions or to employ special fill-in devices to accommodate such odd dimensions as may be involved. In either event, such panels are connected together at adjacent edges by special outside corner fastening strips.

A concrete form panel of the Steel-Ply type, regardless of whether it is used in connection with a wall form, a column form, or a slab form, consists essentially of a shallow tray-like structure including a rectangular plywood facing, the edges of which are completely encased in a rectangular metallic reinforcing frame comprising longitudinal and transverse frame members, together with a series of parallel, spaced apart, transverse crossbars which extend between the longitudinal frame members and lend reinforcement to the medial or central regions of the plywood facing by constituting a backing therefor. Such a panel is adapted to be set up for wall form work in edge-to-edge relationship with similar panels and in such manner that the plywood facings of the panel lie in a common vertical plane. For column form work, the panels are set up in edge-to-edge relationship with adjacent plywood facings extending at a right angle to each other, outside angle irons being required to effect the connections.

In order to accommodate the hardware articles which are used with Steel-Ply panels, the longitudinal and transverse frame members of the rectangular metallic reinforcing frames of the panels are provided with transverse slots, such slots being positioned or located at approximately one-foot centers. Most of the hardware articles that are employed are designed to cooperate with these slots, and included in such hardware articles are conventional T-bolt and wedge assemblies, the latter being employed for drawing the adjacent marginal portions of the panels together and holding them in firmly clamped relation. In order that the various panels may be interlocked with one another, regardless of their position in space, it is necessary that the slots be positioned at equally spaced centers.

F or reasons that relate only to the use of the panels for wall form work, the crossbars of a conventional Steel-Ply panel are in the form of angle pieces which are L-shape in transverse cross section. When installed, the vertical flange of each crossbar fits flatly against the associated plywood facing, thus reinforcing the facing along a relatively wide strip. To preserve end-to-end reversibility of the panels, it has been customary to cause the flanges of the crossbars above a medial horizontal plane to project upwardly and the flanges of the crossbars below such plane to project downwardly.

The concrete column form panels of the present invention, insofar as is practicable, preserve the general structure and appearance of conventional Steel-Ply wall form panels. However, each concrete column form panel is modified in certain respects to enable it to be attached to a like second panel solely by the use of the aforementioned conventional T-bolt and wedge assemblies with the general plane of the two panels extending at a right angle to each other. Moreover, each panel is so designed that it may be attached to such like panel at various transverse regions therealong so that one vertical edge of the first panel traverses the plywood facing of the second panel from end to end in a medial region thereof and so that the two involved plywood facings establish a sealed right angle inside corner for concrete retention when the wet concrete for the column is poured. Since the two panels are substantially identical, the first panel is also capable of having attached thereto a third like panel, one edge of which traverses the plywood facing of the first panel from end to end and in the medial region thereof, thus establishing another right angle inside corner for concrete retention. Similarly, the third panel may be attached to a fourth like panel and the fourth panel may then be applied to the second panel, the four panels establishing a rectangular box-like void into which wet concrete may be poured for column forming purposes. Because the attachment region for an edge of each panel to the adjacent panel is variable across the width of such adjacent panel, and b cause its own width is receptive for attachment of the edge of an adjacent panel in a similarly variable manner, the four panels of the improved system may be assembled upon one another to form a quadrilateral structure embodying such a rectangular box-like void.

In such a quadrilateral box-like structure, the adjacent plywood panel facings approach each other in substantial abutting edge-to-face relationship to provide the four inside corners of the column form. Since means are provided whereby the various abutting edges may be adjustably shifted transversely of the adjacent panel facings, the capacity of the form void may be varied to produce a rectangular concrete column in which the transverse dimension of either pair of opposite sides may be varied in small increments from full panel width to the width afforded by a single increment. For practical considerations, increments of two inches are preferably employed for panel adjustment purposes, such two-inch increments being not only compatible with stress and strain considerations, but also serving to accommodate conventional concrete column specifications insofar as dimensions are concerned.

As will become more readily apparent when the nature of the invention is better understood, conversion of a given column form from a large size to a small size in the successive erection of concrete columns of progressively diminishing dimensions in an upward direction, requires modification of the panels only by the drilling of a few relatively small holes in the panel facings of the employed panels, the holes being only large enough to permit insertion therethrough of the bolts which are employed for holding the panels together. The holes, thus drilled, lie outside the area of concrete contact so that they create no impressions in the finished concrete column.

Moreover, when a second conversion is made for a further reduction in column dimensions and new holes are drilled for this purpose, the new holes, as well as the original holes created for the first conversion, all lie outside of the concrete surface area so that no thought need be given at the scene of operations to hole-filling or other repair operations. Still further, after a given panel has been repeatedly drilled to accommodate the erection of a series of columns which progressively decrease in size, the panel has a further useful life in that it may be returned to the factory or to the shop of the contractor and the panel facing reconditioned by filling in all of the previously drilled holes.

The Steel-Ply concrete column form panels of the present invention retain many of the functional characteristics of conventional Steel-Ply concrete wall form panels and, in fact, they are useable to form a concrete wall form if desired. In particular, the principal feature of conventional Steel-Ply wall form panels whereby adjacent panels may be connected together in edge-to-edge coplanar relationship, either endwise or sidewise, has been retained in the present concrete column form so that for the erection of columns having a dimension wider than that of a single panel, such dimensions may be accommodated by the use of more than one panel along such wider dimens1on. As conversion is made from time to time for the erect-ion of columns of increasing smaller dimensions in an upward direction, when a column dimension is reached WhlCh is equal to or less than the width of a single panel, the additional panel or panels may be omitted and further decreases in dimension may be accommodated on the basis of the single panel. Column height may, of course, be accommodated by the use of column form panels arranged in end-to-end relationship, that is, vertical superimposition.

The provision of a concrete column form and panel therefor such as has been briefly outlined above being among the principal objects of the present invention, numerous other objects will readily suggest themselves as the following description ensues.

In the accompanying three sheets of drawings forming a part of this specification, one illustrative embodiment of a concrete column form panel embodying the invention and its use in two different column form installations are illustrated.

In these drawings:

FIG. 1 is a perspective view of a concrete column form panel which is constructed according to the present invention;

FIG. 2 is a top plan view of a concrete column form assembly employing four of the panels of FIG. 1, the panels being arranged in quadrilateral relationship for the formation or production of a square column having relatively large horizontal dimensions;

FIG. 3 is a top plan view similar to FIG. 2 but showing the four panels arranged for the production of a somewhat smaller concrete column;

FIG. 4 is an enlarged fragmentary outside perspective view illustrating the manner in which adjacent panels in the assembly of FIGS. 2 and 3 are connected together in edge-to-face relationship;

FIG. 5 is a rear perspective view of the structure shown in FIG. 4; and

FIG. 6 is an enlarged sectional view taken substantially along the vertical plane represented by the line 66 of FIG. 1 and in the direction indicated by the arrows, the view further showing in exploded fashion the manner in which a second panel may be juxtapositioned with respect to a first panel in edge-to-face relationship to produce an inside column form corner.

Referring now to the drawings in detail and in particular to FIG. 1, a concrete column form panel embodying the principles of the present invention is illustrated in this view and designated in its entirety by the reference numeral 10. The panel 10 is of the prefabricated Steel-Ply type. It is of open shallow tray-like design and comprises a rectangular plywood facing 12 and a marginal rectangular steel reinforcing frame. The latter includes longitudinal frame members 14 and transverse frame members 16. The panel 10 is shown in FIG. 1 as being positioned with its longitudinal frame members 14 extending vertically and with its transverse frame members 16 extending horizontally, this being the normal position of the panel when employed with similar panels in a concrete column form. Thus, further reference to the panel 10 may be made on the basis of its vertical position in a column form.

At appropriate levels in the panel 10, intermediate horizontal crossbars 20 extend between and are welded to the opposed vertical frame members 14. As best seen in FIGS. 4 and 5, these crossbars 20 are of a composite nature and are in the form of upper and lower angle pieces 22 and 24. The latter have horizontal flanges Welded together in face-to-face relationship and vertical flanges positioned in face-to-face contact with the plywood facing 12, the composite crossbars thus presenting a generally T-shape cross section. For exemplary purposes, seven crossbars have been illustrated in the form of panel that is shown in FIG. 1, but it will be understood that a greater or lesser number of such crossbars may be employed if desired. The four crossbars 20 in the upper regions of the panel 10 are provided with rows of horizontally elongated slots 26 in the vertical flanges of the lower angle pieces 24, while in the lower regions of the panel 10 the three crossbars 20 are provided with similar rows of slots in the vertical flanges of the upper angle pieces 22. The various slots 26 open directly onto the outside face of the plywood panel facing 12 and are provided for a purpose that will be made clear presently.

The frame members 14 and 16 are in the form of structural steel bars which are of shallow channel shape so far as cross section is concerned. Each bar includes inside and outside outwardly extending marginal ribs 27 and 2S, and a connecting base or Web 30. On the side of each web that is opposite to the ribs 27 and 28 is a lateral inwardly extending flange 32 on which the adjacent edge portion of the plywood facing 12 seats with its inside face flush with the inside edges of the frame members 14 and 16.

At vertically spaced regions along the marginal ribs 27 and 28, pairs of transversely registering notches 34 are cut and these notches, when the frame members are in contiguity with the frame members of adjacent panels,

define channel voids through which the looped ends of tie rods (not shown) may pass when the panel is employed as a wall form panel or when the same is disposed in coplanar contiguity with a similar panel in a column form that is designed or adapted for the production of an extremely large dimension concrete column. A rectangular slot 36 is formed in the web portion 30 of each frame member at the level of each pair of notches 34 and such slot is adapted to receive therethrough the shank portion of the T-bolt of a T-bolt and wedge assembly (not shown) whereby the contiguous or abutting frame members of adjoining coplanar panels may be drawn tightly towards one another and maintained in clamped-together relationship. The manner in which adjacent panels 10 may thus be connected together in coplanar relationship and maintained spaced from similarly connected panels on the opposite sides of a wall form installation is well known in the art and, therefore, has not been illustrated herein. This manner of connection is a basic feature of Steel-Ply panels and has been employed since the advent of such panels. For a full disclosure of the use of tie rods and T-bolt and wedge assemblies for panel clamping and form side spacing purposes in connection with a concrete wall form, reference may be had to United States Patent No. 2,948,045, granted on Aug. 9, 1960, and entitled, Tie Rod Assembly for Concrete Wall Forms and Cone Therefor. The disclosure herein of shallow channel-shaped frame members 14 and 16 with notches 34 in the ribs 27 and 28 has been made for the purpose of illustrating the fact that coplanar attachment of adjacent panels 10 in either a wall form or a column form installation may be made if desired and that this basic feature of conventional Steel-Ply panels has been preserved in the present column form panel 10.

The various slots 26 in the vertical flanges of the upper and lower angle pieces of the crossbars 20 are preferably spaced apart on two-inch centers, these slots making it possible to effect incremental adjustment of the positions of adjacent panels 10 in connection with a quadrilateral arrangement of panels such as illustrated in FIGS. 2 and 3 when erecting a concrete column form installation. Before describing the column form installations of FIGS. 2 and 3, it is important to point out that the various slots 36 in the web portions 30 of the vertical frame members 14 are on the same horizontal centerline as the adjacent rows of slots 26 in the vertical flanges of the upper and lower angle pieces of the crossbars 20, whether these rows of slots be in the upper angle pieces 22 or the lower angle pieces 24, this alignment of slots 26 and 35 being made for the purpose of conveniently accommodating the use of T-bolt and wedge fastening assemblies like that shown at 40 in FIGS. 4 and 5 when attaching adjacent panels 10 together in edge-to-face relationship in a concrete column form installation as will now be more fully described.

Referring now to FIGS. 2 to 5, inclusive, a column form 42 employing four of the panels 10 in a quadrilateral relationship is shown in FIG. 2, the particular concrete column to be formed being square in cross section and of appreciable horizontal dimensions. In FIG. 3, the same panels 10 are shown in a different quadrilateral relationship in a concrete column form 44 which is designed to produce a square column of smaller dimen sions. It will be understood that various rectangular quadrilateral relationships other than square are contemplated. In FIGS. 4 and 5, there are shown the details of the connecting or attaching hardware by means of which the quadrilateral relationship of the panels in the forms 42 and 44 is maintained.

Referring now specifically to FIG. 2, the column form 42 is comprised of four of the panels 10 which are so disposed as to produce a quadrilateral arrangement wherein one vertical frame member 14 of each panel seats against the plywood panel facing 12 of an adjacent panel and, in turn, has its own panel facing disposed in line contact with one of the vertical frame members 14 of a third panel 10, the four panels establishing a rectangular box-like form structure within which wet coincrete is adapted to be poured to produce, when hardened, a concrete column.

'When the four panels 10 are thus disposed, the various crossbars 20 that are associated therewith and form a part thereof will lie in a series of seven common levels whereby, at each level, one of the slots 36 in the vertical frame member 14 of each panel 10 may be brought into horizontal register with a selected slot 26 in one of the horizontal crossbars 20 of an adjacent panel (see FIGS. 4 and 5) so that the shank of a conventional T-bolt, such, for example, as the bolt 45 may be passed through the two registering slots and thereafter secured in position by a conventional wedge 46. In order to create a passage for the shank portion of the T-bolt 45, it is first necessary to remove a portion of the panel facing 12 in the immediate vicinity of the two registering slots 36 and 26 and this may conveniently be done by cutting a circular hole 48 through the plywood facing with a cylindrical core drill which may be caused to penetrate the plywood to a degree just sufiicient to pass through the plywood and not damage the underlying crossbar, the hole being in register with the two registering slots 36 and 26. The creation of such a hole 48 is illustrated schematically in FIG. 7 and the removed plug is shown at 50.

The T-bolt 45 and the wedge 46 constitute the counterparts of the aforementioned conventional fastening assembly 40 which with like assemblies is used for connecting adjacent conventional Steel-Ply panels together in the manner illustrated in aforementioned Patent No. 2,948,045, and in the present use of such an assembly, the head of the T-bolt 45 of the assembly bears against the crossbar 20 of one panel 10 and the wedge 46 of the assembly is driven downwardly through a slot in the shank portion of the T-bolt 45 in such manner as to cause one edge thereof to bear against the web portion 30 of the vertical frame member 14 of the adjacent panel 10, thus drawing the frame member 14 of the second panel hard against the plywood facing of the first panel along a mediately disposed vertical line extending from top to bottom of the first panel. By causing each plywood facing 12 of the four panels 10 similarly to receive thereagainst the vertical frame member 14 of an adjacent panel, the wide quadrilateral structure of FIG. 2 may be erected.

In FIG. 3 a similar arrangement of four panels 10 establishing the column form 42 is disclosed. In the form 42, the slots 26 in the various crossbars 20 which are more centrally disposed than is the case in connection with the form 40 have been selected for reception of the shank portions of the T bolts 45. This produces a square concrete-receiving void of smaller dimensions than the square void that is associated with the form 44. Otherwise, the method of assembly or erection of the form 42 remains the same.

It will be understood that in preparing the panels 10 of the form 42 for reception therethrough of the shank portions of the T-bolts 45, holes such as the holes 48 must be cut through the plywood in the vicinity of the registering slots 36 and 26 as is the case in connection with the larger form 42. These holes are in addition to the previously cut holes 48 since the panels 10 of the form 44 are considered to be the same panels which were previously used in the construction of the form 42. When the panels 10 are arranged in the quadrilateral relationship shown in FIGS. 3, 4 and 5, the previously cut holes 48 lie outside the confines of the concretereceiving void that is produced by the form and, therefore, their presence in the plywood facings 12 has no adverse effect upon the exterior surface of the finished concrete column. These holes may be allowed to remain in the plywood facings of the various panels 10 during successive and progressively smaller form installations until such time as the panels are returned to the factory or shop for reconditioning, at which time they may be appropriately filled-in with a suitable wood filler material.

It is to be further noted at this point that when the four panels 10 are arranged in quadrilateral relationship to produce the form 42 or the form 44 or a concrete column form of a different size, the seven common levels of crossbar inclusion will obtain regardless of whether the panels be erect as shown in FIG. 1 or inverted. The attainment of such common levels is made possible by causing the slots 36 in the vertical frame members of each panel 10 to have equal spacings even though the two adjacent crossbars 20 in the central region of the panel are spaced apart a greater distance than is the spacing between the other adjacent pairs of crossbars. Such unequal crossbar spacing is the result of the formation of the slots 26 in the upper angle pieces 22 of certain crossbars and in the lower angle pieces 24 of certain other crossbars. This irregularity of crossbars is concerned with clearance space for the installation of various forms of concrete wall form hardware and other factors not pertinent to the present invention.

It is to be further noted that in order to permit downward driving of the wedges 46 through the slots in the shank portions of the associated T-bolts when erecting a concrete column form such as the form 42 or the form 44, clearance slots 60 (see FIG. are formed in the two face-to-face horizontal flanges of the associated crossbars 20 and these clearance slots immediately underlie the slots in the shank portions of the T-bolts 45 when the latter are inserted through the slots 36 and 26.

Finally, it is to be noted that whereas in connection with conventional Steel-Ply panels for use in connection with wall form installations, the crossbars that are associated therewith are in the form of single angle pieces having vertical flanges in face-to-face contact with the plywood facings, the present panel It) employs for each crossbar two angle pieces 22 and 24 which are arranged in contiguity and are welded together, as previously set forth, such arrangement being provided to make up for the lack of rigidity that is occasioned by the provision of the large number of closely spaced slots 26 in one vertical flange of each crossbar. Due to the somewhat wider area of metal-to-wood contact between the crossbars 20 and the plywood facing 12 of the panel 10, the vertical dimension of the included opening between adjacent crossbars is decreased to a certain extent, this being an advantageous feature in that outward bulging of the plywood facing in the regions of such included openings is resisted more advantageously than is the case in connection with conventional Steel-Ply wall form panels having one-piece crossbars.

Although the panels have been illustrated and described in connection with the erection of concrete column form installations, such as the installations 42 and 44, involving only four of the panels 10, it will be understood that if a contemplated concrete column has a dimension greater than that which may be accommodated by the width of a single panel, then two or more such panels may be disposed in coplanar and edge-toedge relationship and secured together in the conventional manner of concrete wall form installation by means of a proper number of the T-bolt and wedge assemblies 40. The several panels thus secured together may be caused to serve as one side of a quadrilateral column form structure or installation and other similarly connected panels may be caused to serve for the remaining sides of the structure or installation. Since the crossbars 20 will assume several common levels within the form structure, the slots 26 therein along substantially the entire combined length of such crossbars as fall into end-to-end alignment are then available for edge-toface connection between the adjacent panels. In the successive erection of forms of progressively diminishing size, when a point has been reached where the column dimensions are sufliciently small that they may be accommodated by individual panels, the panels of the coplanar and edge-to-edge panel assemblies may be disconnected from each other, and the particular panels, whose plywood facings have not yet been cut or drilled to provide holes such as the holes 48, may then be employed singly for the production of the individual sides of the smaller concrete column form.

The inventon is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specification as various changes in the details of construction may be resorted to without departing from the spirit or scope of the invention. For example, while the invention has been described particularly in connection with the erection of column forms, it will be understood that panels manufactured in accordance with the principles of the present invention may, with or Without modification as required, be employed in the erection of forms where various odd dimensions are involved requiring a right angle corner at a region where a standard size panel which otherwise would accommodate such a corner is not available. The particular panel selected for exemplary illustration herein follows the general pattern of a conventional eight-foot length Steel-Ply panel. In such an instance, it is customary to employ seven intermediate crossbars for panel-facing reinforcement purposes. Where panels 10 of lesser height are constructed, it will be understood that a lesser number of crossbars will be employed, all in accordance with engineering expediencies which have been developed in connection with the production of Steel-Ply panels over a long period of time. Therefore, only insofar as the invention is particularly pointed out in the accompanying claims is the same to be limited.

Having thus described what I claim as new and desire to secure by Letters Patent is:

1. In a concrete form assembly, a first vertical rectangular panel comprising a rectangular plywood facing bounded by a marginal steel frame including opposed vertical and opposed horizontal frame members which project laterally from the general plane of the facing in the same direction thus defining a shallow tray-like structure, a first series of vertically spaced horizontally disposed composite steel crossbars extending between the opposed vertical frame members above the level of the horizontal mid-plane of the panel, a second series of vertically spaced horizontally disposed composite steel crossbars extending between the opposed vertical frame members below the level of said horizontal mid-plane, each of said crossbars consisting of upper and lower angle pieces having abutting horizontally extending flanges welded together in face-to-face contact and presenting coplanar vertical flanges which extend in opposite directions so that the vertical flange of the upper angle piece projects upwardly and the vertical flange of the lower angle piece projects downwardly, the vertically extending flange of the lower angle piece of each crossbar which lies above said horizontal mid-plane of the panel having formed therein a row of equally and horizontally spaced, horizontally elongated slots, the vertically extending flange of the upper angle piece of each crossbar which lies below said horizontal mid-plane having formed therein a similar row of equally and horizontally spaced, horizontally elongated slots, each vertical frame member being formed with a series of vertically spaced, horizontally elongated slots which lie on the centerlines of the rows of slots in the angle pieces of the crossbars, the ends of the abutting horizontal flanges of each crossbar having formed therein clearance slots, a second similar panel positioned in edge-to-face contact with the first panel with the slots in one of its longitudinal frame members in register with one series of vertically aligned slots in the angle pieces of the crossbars of the first panel, a

,removable T-bolt having a slotted shank portion projecting through each pair of registering slots and through the plywood facing of the first panel and, in addition, an enlarged head bearing against the adjacent crossbar, and a Wedge projecting through said shank portion and hear ing against the adjacent vertical frame member and serving to draw the frame member hard against the panel facing, the lower ends of all of the wedge projecting downwardly through an underlying clearance slot in the adjacent crossbar.

2. In a concrete column form assembly, a series of substantially identical vertically disposed panels arranged in quadrilateral relationship so as to define therebetween and enclosed rectangular void into which wet concrete is adapted to be poured to produce a vertical column, each panel being comprised of a rectangular plywood facing bounded by a marginal steel frame including opposed vertical and opposed horizontal frame members which project laterally from the general plane of the panel facing in the same direction thus defining a shallow tray-like structure, a plaurality of vertically spaced horizontally disposed composite steel crossbars extending between the opposed vertical frame members and bearing against said panel facing coextensively across the latter along narrow band-like regions above and below the horizontal mid-plane of the panel, each crossbar consisting of upper and lower angle pieces having abutting horizontal flanges welded together in face-to-face relationship and presenting coplanar vertical flanges which lie flush against the playwood facing and extend in opposite directions so that the vertical flange of the upper angle piece projects upwardly and the vertical flange of the lower angle piece projects downwardly, the vertically extending flange of the lower angle piece of each crossbar which lies above said horizontal mid-plane of the panel having formed therein a row of equally and horizontally spaced, horizontally elongated slots which open directly onto the ad- 10 jacent face of the plywood facing, the vertically extending flange of the upper angle piece of each crossbar which lies below said horizontal mid-plane having formed therein a similar row of slots, said vertical frame members each being formed with horizontally elongated slots which lie on the centerlines of the rows of slots in the angle pieces of the crossbars, one vertical frame member of each panel bearing against the panel facing of an adjacent panel with the slots in said one vertical frame member in horizontal register with adjacent slots in the angle pieces of the crossbars of such adjacent panel, means projecting through each pair of registering slots, and the interposed plywood panel facing and serving to clamp said one vertical frame member hard against the panel facing of the adjacent panel member, said means including a T-bolt having an enlarged head hearing against the adjacent crossbar and a slotted shank, and a wedge projecting vertically through said slotted shank and bearing against the adjacent vertical frame member.

References Cited UNITED STATES PATENTS 1,640,997 8/1927 Hollister 249-192 2,582,168 1/1952 Sato 249-49 2,595,286 5/1952 Otte et al. 249-49 2,640,249 6/1953 Symons 249-191 2,975,498 3/1961 Plattner 249-48 3,067,479 12/1962 Schimmel 249-214 X 3,246,871 4/1966 Bowden 249-192 X FOREIGN PATENTS 621,069 1961 Italy.

WILLIAM J. STEPHENSON, Primary Examiner. 

1. IN A CONCRETE FORM ASSEMBLY, A FIRST VERTICAL RECTANGULAR PANEL COMPRISING A RECTANGULAR PLYWOOD FACING BOUNDED BY A MARGINAL STEEL FRAME INCLUDING OPPOSED VERTICAL AND OPPOSED HORIZONTAL FRAME MEMBERS WHICH PROJECT LATERALLY FROM THE GENERAL PLANE OF THE FACING IN THE SAME DIRECTION THUS DEFINING A SHALLOW TRAY-LIKE STRUCTURE, A FIRST SERIES OF VERTICALLY SPACED HORIZONTALLY DISPOSED COMPOSITE STEEL CROSSBARS EXTENDING BETWEEN THE OPPOSED VERTICAL FRAME MEMBERS ABOVE THE LEVEL OF THE HORIZONTAL MID-PLANE OF THE PANEL, A SECOND SERIES OF VERTICALLY SPACED HORIZONTALLY DISPOSED COMPOSITE STEEL CROSSBARS EXTENDING BETWEEN THE OPPOSED VERTICAL FRAME MEMBERS BELOW THE LEVEL OF SAID HORIZONTAL MID-PLANE, EACH OF SAID CROSSBARS CONSISTING OF UPPER AND LOWER ANGLE PIECES HAVING ABUTTING HORIZONTALLY EXTENDING FLANGES WELDED TOGETHER IN FACE-TO-FACE CONTACT AND PRESENTING COPLANAR VERTICAL FLANGES WHICH EXTEND IN OPPOSITE DIRECTIONS SO THAT THE VERTICAL FLANGE OF THE UPPER ANGLE PIECE PROJECTS UPWARDLY AND THE VERTICAL FLANGE OF THE LOWER ANGLE PIECE PROJECTS DOWNWARDLY, THE VERTICALLY EXTENDING FLANGE OF THE LOWER ANGLE PIECE OF EACH CROSSBAR WHICH LIES ABOVE SAID HORIZONTAL MID-PLANE OF THE PANEL HAVING FORMED THEREIN A ROW OF EQUALLY AND HORIZONTALLY SPACED, HORIZONTALLY ELONGATED SLOTS, THE VERTICALLY EXTENDING FLANGE OF THE UPPER ANGLE PIECE OF EACH CROSSBAR 